This invention relates to retention pins used to retain liner segments of tumbling mills, such as casting shake-out units, dual sand reclaimers, lump crushers, media drums, and the like, in place and in particular to a double sided retention pin which may be used in two positions in the tumbling mill.
Casting shake-out units and other types of tumbling mills frequently have inner linings formed from liner segments. When individual segments wear out, the segments can be replaced easily and rapidly without incurring a significant amount of machinery or plant down time. Further, the liner can be repaired without having to replace the entire lining. An example of such a unit is disclosed in U.S. Pat. No. 3,998,262 which shows a segmented inner cylinder or liner for a casting shake-out unit. As explained therein, the internal cylinder forming the inner surface of the unit is constructed from a series of modular components. The components or segments fit together to form the lining of the shake-out unit. The operation of that particular unit, for its purpose, has performed highly satisfactorily. However, when the casting shake-out unit is operated continuously, the wear from the continuous operation can cause the liner segments to gradually loosen. The segments must then be retightened by welding the segments together. If the segments are not retightened, the segments could eventually separate, causing the lining to come apart.
This situation was remedied by the retention pin system disclosed in U.S. Pat. No. 4,502,808, which is assigned to the same assignee as the present invention, and which is incorporated herein by reference. As disclosed in that patent, the liner segments are provided with rectangular channels along adjacent edges of the liner segments. Retention pins are received in the channels to urge the liner segments apart, thereby creating a tight interfit among the segments. The pin or rod disclosed therein is formed having a series of inherent angular bends and is constructed of resilient material. The rod thus has a slight spring quality. As the rod is forcefully inserted in place in the channels between pairs of liner segments, the rod acts to exert a pressure against adjacent segments to assure their tightness in interfitting together to form the liner for the a casting shake-out unit or the like. However, when the segments are formed, the clearance between adjacent segments is not constant. Thus, depending on the size of the clearance, the retention rod may be too large to fit in the channel between the segments, or the rod may be too small, and may not operate to properly tighten the liner in place.